The sleigh-bell chorus of tree frogs provides backing vocals for the clucking of the southern leopard frogs in the marsh. We first heard the sound of the leopard frog here about seven years ago. On the Anne Arundel-Calvert border, the marsh is home to osprey, killdeer, red-winged black birds, muskrats, raccoons and many frogs.

It used to be thought that frogs were created by late winter rains. Now we know that in March, the leopard frogs migrate from the damp woods bordering the marsh. During or after a late winter rain, they come down to an even wetter place to mate. The calls, raucous and comical, are the males' way of finding females.

The females will lay a round mass of three to five thousand eggs in ponds and pools. Some of the eggs will become tadpoles. Some of the tadpoles will metamorphose to adult - if they are not preyed on or run over by cars, and if their backwater puddles do not dry up first.

Like some other amphibians, these frogs require a complex arrangement of habitats to complete their life cycle. The egg and tadpole stages are spent underwater in vernal pools or marshes, almost any body of fresh water. Adults live in the slightly upland woods. Wetlands and woods are what they need, plus one more thing: corridors for migration. No woods, no frogs. No wetlands, no frogs. No corridors, no frogs, toads nor salamanders either.

The sleepy little community just north of the marsh is undergoing a metamorphosis, too. A few years ago, water and sewer service came; there has been a dramatic build-out since. Now the wet, wet woods will be transformed to a subdivision. The signs have been posted.

The marsh will remain; it might not look much different, on the surface. Frogs will return, for they will not be extirpated by one subdivision, not entirely. But the new streets and buildings will rearrange the mosaic of upland, wetland and water. The repercussions will reverberate from the amphibians up the food chain.

Yes, we live in a house and drive the road that first sliced through that froggy world many years ago. And there are other subdivisions, carving up similar places not so far away. We all gotta live somewhere, and driving is the only transportation in this town.

The southern leopard frog grows to an average length of 3.5 inches. They can be distinguished from the northern leopard frogs by the white spot on the tympanum, which is the sound-sensitive organ on the sides of their heads.

The frogs haven't heard the news, and their clucking calls don't have a message for us. But if I may assume to speak for them, I would advocate for preservation of wetlands and forests; for smart growth and planning and warm rain.